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BACKGROUND/RATIONALE:
Patient non-adherence with medical therapy continues to be a problem in essentially all medical specialties, especially among patients with asymptomatic chronic conditions such as diabetes, hypertension and hypercholesterolemia. Methods of measuring medication adherence including the Morisky Instrument, a validated four item self reported scale measuring medication-taking behavior and calculation of medication adherence rates using pharmacy records have been incorporated into numerous trials assessing medication non-adherence in a variety of disease states including diabetes, hypertension and hypercholesterolemia. Other studies have shown that there is only modest correlation between self report and pill refill measures of adherence. To date these studies have not been published on VA data . Additionally, while both measures of adherence are associated with clinical outcomes, no direct comparison between the two exist with regards to strength of the association with these outcomes.
OBJECTIVE(S):
The objective of this study is to directly compare ReComp, a calucation of VA pharmacy refill data, to the Morisky, a self reported adherence scale among 239 patients enrolled in Can Group Visits Improve Outcomes of Veterans with Diabetes? (study IIR-03-084) Specific Aims include: 1) to measure the agreement between ReComp and the Morisky self reported measurement of adherence among patients 2) to evaluate the strength of association between ReComp and Morisky with change in A1c, LDL and systolic blood pressure 3) determine if either medication adherence measure is associated with the efficacy of the diabetes group visit intervention.
METHODS:
The project contains 2 study designs: A cross-sectional study performed on the baseline data study IIR-03-084) and a prospective observational study nested within the group visit diabetes trial. All subjects were patients enrolled in 03-084 who receive primary care at the Richmond or Durham VA Medical Centers, have diabetes (A1c > 7.5%) and hypertension. For all analyses, Morisky will be dichotomized as perfect vs. imperfect self-reported adherence. Claims data for antihypertensive, diabetes and lipid lowering therapy prescriptions will be exported from the Veterans Affairs Health Information System Technology Architecture (VISTA) database to Microsoft Excel for patients enrolled in 03-084. Medication adherence will be calculated by applying the ReComp algorithm to local VA pharmacy records (i.e., medication name, date dispensed, and the number of days supply dispensed). We will use ReComp to calculate patients available supply of oral hypoglycemic, anti-hypertensive and lipid lowering medications prescribed for each patient at enrollment, 6 months and 12 months after enrollment. After calculating the mean of the 90-day class-specific acquisition measures, the final step is to convert this continuous measure to a dichotomous variable. Previous studies (21-24) have classified values less than 0.80 as undersupply, values of 0.80 to 1.20 as appropriate supply, and values greater than 1.20 as oversupply. Thus, we will dichotomize ReComp into appropriate (ReComp =0.8-1.2) and inappropriate supply.
FINDINGS/RESULTS:
More than 95% of patients included are male, age > 50 and have had diabetes for > 10 years. The mean HbA1c at enrollment was 9.2% and mean SBP was > 151 mmHg. Patients enrolled in the IIR-03-84, completed the Morisky measurement of self report at baseline, 6 month and 12 month follow-up.
IMPACT:
Findings from this study will allow VA investigators to make inference about the relative strengths and weaknesses of various adherence measures as outcomes and covariates in research studies. Additionally, we may discover the impact of changing adherence on the potency of health services interventions.
PUBLICATIONS:
None at this time.
DRA:
Health Services and Systems
DRE:
none
Keywords:
none
MeSH Terms:
none
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